Generally, as a magnetic disc of a thin film type, there is used such that NiP is polished on a Al base as a substrate. As a means for giving a magnetic anisotropy of a magnetic disc using this substrate to a circumferential direction which is a head running direction, there is a process for applying texturing [texturing means attaching fine scratches by a grinding tape in circumferential direction] to a surface of a substrate. On a substrate texturing treated is formed Cr film followed by forming a Co alloy film to obtain a magnetic recording medium. For using as products, it is necessary to provide a carbon film, as a lubricating layer, upon which a lubricating layer is formed.
Recently, as a high density is achieved in magnetic recording, so narrow track, narrow gap, narrow spacing between head and disc, etc. have been intended to achieve as a countermeasure. However, these countermeasures involve the effect or restriction of magnetic properties or mechanical properties of magnetic discs. Therefore, in magnetic discs, improvement of circumferential magnetic orientation or obtaining a high Hc (coercive force) is intended to achieve. Further, as a countermeasure of narrow spacing between head and disc, it is necessary to secure a smooth surface without a small and fine projection. Under such circumstances, it is a glass substate which is a smooth base to be noted. In this point if magnetic property which has been obtained in conventional NiP/Al substrate is secured, hopeful high density magnetic recording medium is considered to be undoubtly obtainable.
However, even if a glass substrate is subjected to texturing treatment similarly to the conventional to film form Cr or Co alloy, magnetic anisotropy is isotropic in surface. A result similar to this case is caused irrespective of texturing treatment on a glass substrate and therefore it is proved that texturing treatment has no advantage. As magnetic anisotropy lacks as mentioned above, there has been such a disadvantage that, in a similar sputtering condition, the value of Hc becomes low comparing with said conventional NiP texturing/Al substrate.